I get the opposite impression. Stale software organisations with steady operating products seem to use massive headcounts, whereas startups building new products often get by with relatively few people.
Plus at least monthly if not daily, even hourly system patching.
Planting a garden is one thing.
Weeding it is another.
90% of startups fail within 5 years so probably not the best example of how to run things.
The few that do "succeed" often carry over mountains of cruft and garbage code into perpetuity (for example Reddit).